Tendinous insertion of semimembranosus muscle into the lateral meniscus.
Forty-two cadaver knees were used for morphologic and MRI observations of the tendinous distal expansions of the semimembranosus m. and the posterior capsular structures of the knee. A tendinous branch of the semimembranosus m. inserting into the posterior horn of the lateral meniscus was found in 43.2% of the knees dissected, besides five already known insertional branches; capsular, direct, anterior and inferior, as well as the oblique popliteal ligament. The tendon had three morphologic types; thin, broad and round. All three types moved the lateral meniscus posteriorly when pulled on. Thus, the semimembranosus m. may also have a protective function for the lateral meniscus as well as the already well established function of protecting the medial meniscus in knee flexion. When a semimembranosus tendon attachment to the posterior horn of the lateral meniscus is present, its normal insertion is difficult to differentiate from a lateral meniscus tear in MRI and this may cause misdiagnosis.
Kim
Y C
YC
Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.
Yoo
W K
WK
Chung
I H
IH
Seo
J S
JS
Tanaka
S
S
D014644:Genetic Variation; D006801:Humans; D007717:Knee / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging; D008592:Menisci, Tibial / Q000033:anatomy & histology*; D013710:Tendons / Q000033:anatomy & histology